Offset madness

The outside offset in your image above isn’t correct either - IMO, it should look like this (sharp corners):

(try it with round corners and you will see it works better)

The offset code for Breps is also not robust - especially with sharp corners - if you try any complex polysurface in Rhino with OffsetSrf or Shell, you will see.

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agreed to that i tried to model simple rectangular underpass under railtrack. offsetsrf polysurface of innerwalls and it failed. i compared to microstation with the same geometry and there was no problem. i posted it here, others said parasolid is much better (more expensive) but i am asking where should development go with rhino. its version 7 and these are basic geometric operations which should have been resolved since earlier versions. thats why i think there would be room for rhino next similarly to vray next. no evolution but revolution

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I can reassure you that you are not the only one feeling this.

Just for fun, as I was running some toolpaths this afternoon - here is RhinoCAM’s outside profiling offset with a 6mm cutter (the ‘slot’ is 5mm wide)…


Note I didn’t find how to square off the corners near the slot, but it’s a correct offset - normally all corners are rounded for nicer milling, but I forced “sharp corners” where I could.

Here is the inside offset with a 16mm tool (the inner space in the lower left corner is 15mm wide):


Again, not able to force sharp corners on the external corners though.

This offset based on toolpath radius it is always rounded.